The present invention relates generally to operations performed, and equipment used, in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides a releasable no-go tool and associated methods.
In many circumstances, it is desirable to position an item of equipment in a particular location in a well. For example, a whipstock may be positioned in a casing string to permit a lateral wellbore to be formed by cutting a window in the casing string and drilling the wellbore through the window, a perforating gun may be positioned to perforate the casing string at a particular location, etc.
One method of accurately positioning an item of equipment that has been used in the past is to interconnect an internal no-go shoulder in the casing string when it is installed in the well. In this way, a tubing string subsequently lowered into the casing may include an external no-go shoulder so that, when the internal and external shoulders engage each other, the tubing string is positively positioned relative to the casing string. If the item of equipment is interconnected in the tubing string a known distance from the external no-go shoulder, then upon engagement of the shoulders, the position of the item of equipment in the well is determined.
Unfortunately, the above method is not satisfactory in some situations. For example, where operations are performed from a floating rig, it may be difficult to maintain engagement of the shoulders, due to the tubing string rising and falling with the floating rig. When working from a land-based rig, situations may also arise which make it difficult to maintain engagement of the shoulders while enabling other operations to be performed unhindered. Additionally, it is costly to provide the no-go shoulder in the casing string, and the selection of the no-go shoulder depth in the casing string is limited by structural casing constraints.
From the foregoing, it can be seen that it would be quite desirable to provide a no-go tool and associated methods which permit accurate positioning of items of equipment in a subterranean well.
In carrying out the principles of the present invention, in accordance with an embodiment thereof, a releasable no-go tool is provided. Methods of releasably securing an item of equipment in a wellbore are also provided.
In one aspect of the present invention, a releasable no-go tool has a housing with an internal axial flow passage. A key is carried on the housing. The key is outwardly biased by a piston when a pressure is applied to the flow passage.
The key may be circumferentially continuous and may circumscribe the housing. This key construction permits increased contact area between the key and an internal profile of a casing string in which the tool is received. The key may also inwardly bias itself when it is outwardly biased by the piston, so that the key may inwardly retract when pressure is relieved from the piston.
In another aspect of the present invention, a method of releasably securing an item of equipment in a wellbore includes the steps of positioning a first tubular string within the wellbore, the first tubular string including a nipple having an internal profile; positioning a second tubular string within the first tubular string, the second tubular string including the item of equipment and a releasable no-go tool having at least one key; applying a first pressure to the second tubular string, thereby extending the key radially outward from the second tubular string; and engaging the key with the profile, thereby securing the item of equipment relative to the first tubular string.
In yet another aspect of the present invention, a downhole equipment positioning system is provided. The system includes a nipple interconnected in a casing string cemented in a well. The nipple has an internal profile. A tubing string is reciprocably received within the casing string. The tubing string includes a tool with at least one key, which is outwardly displaced into engagement with the profile by applying pressure to the tubing string.
These and other features, advantages, benefits and objects of the present invention will become apparent to one of ordinary skill in the art upon careful consideration of the detailed description of representative embodiments of the invention hereinbelow and the accompanying drawings.